Painted Turtle Size: How Big Do They Get? (With Subspecies Breakdown)
This post was created with help from AI tools and carefully reviewed by a human (Muntaseer Rahman). For more on how we use AI on this site, check out our Editorial Policy.
Adult painted turtles grow between 4 to 10 inches in shell length, depending on their subspecies and sex. The Western painted turtle is the largest at 7-10 inches, while the Southern painted turtle is the smallest at 4-6 inches.
Size matters when you’re planning tank space or wondering if that turtle you spotted is fully grown. Different painted turtle subspecies grow to vastly different sizes.
In this guide, you’ll learn exactly how big each painted turtle subspecies gets, the size differences between males and females, how fast they grow, and what factors affect their final size.
Quick Answer: Painted Turtle Size at a Glance
- Western Painted Turtle: 7-10 inches (largest subspecies)
- Eastern Painted Turtle: 5-7 inches
- Midland Painted Turtle: 5-7 inches
- Southern Painted Turtle: 4-6 inches (smallest subspecies)
- Female Size: Always larger than males (up to 2 inches bigger)
- Hatchling Size: About 1 inch (size of a quarter)
How Big Do Painted Turtles Get By Subspecies?
Not all painted turtles grow to the same size. Where they live makes a huge difference.
Western Painted Turtle Size
Western painted turtles are the giants of the family. Adults typically reach 7-8 inches, with females often hitting 10 inches.
The record size for this subspecies is 9.8 inches. They’re found from Canada down through the western United States.
Eastern Painted Turtle Size
Eastern painted turtles are medium-sized. Males grow 5-6 inches long, while females reach 6-7 inches.
These turtles are found along the Atlantic coast. They rarely exceed 7 inches even under ideal conditions.
Midland Painted Turtle Size
Midland painted turtles match the Eastern subspecies in size. They grow to 5-7 inches in shell length.
This subspecies lives in the Great Lakes region and Ohio River valley. They’re medium-sized but stockier than their Eastern cousins.
Southern Painted Turtle Size
Southern painted turtles are the runts of the family. Adults typically measure just 4-5 inches, occasionally reaching 6 inches.
Their smaller size is thought to help them compete with other turtle species in their range. They live along the Mississippi River and Gulf Coast.
This Hilarious Turtle Book Might Know Your Pet Better Than You Do
Let’s be real—most turtle care guides feel like reading a textbook written by a sleep-deprived zookeeper.
This one’s not that.
Told from the snarky point of view of a grumpy, judgmental turtle, 21 Turtle Truths You’ll Never Read in a Care Guide is packed with sarcasm, sass, and surprisingly useful insights.
And hey—you don’t have to commit to the whole thing just yet.
Grab 2 free truths from the ebook and get a taste of what your turtle really thinks about your setup, your food choices, and that weird plastic palm tree.
It’s funny, it’s honest, and if you’ve ever owned a turtle who glares at you like you’re the problem—you’ll feel seen.
Male vs Female Painted Turtle Size
Female painted turtles grow way bigger than males. It’s one of the easiest ways to tell them apart.
Adult males reach 5-8 inches depending on subspecies. Females grow 6-10 inches – sometimes 2 full inches longer than males.
This size difference exists for a practical reason. Females need larger bodies to produce and carry eggs.
Males mature faster but stop growing sooner. Females take longer to mature but keep growing for more years.
In the Western subspecies, males max out around 6-7 inches. Females of the same subspecies can hit 10 inches.
This size gap becomes really obvious once both turtles reach full maturity around 5-7 years old.
Baby Painted Turtle Size
Hatchlings are tiny – about the size of a quarter. They measure roughly 0.7-1.2 inches in shell length.
When they first pop out of the egg, they weigh just 2.6-5.8 grams. That’s lighter than two pennies.
These babies are basically bite-sized snacks for predators. Only 19% survive their first year in the wild.
How Fast Do Painted Turtles Grow?
Painted turtles grow like crazy during their first year. Many double in size, reaching 2-3 inches by their first birthday.
Growth slows down significantly after year one. By age 2-3, they’re usually 3-4 inches long.
Here’s the typical growth timeline:
- Year 1: 1 inch → 2-3 inches (rapid growth)
- Year 2-3: 3-4 inches (moderate growth)
- Year 4-5: 4-6 inches (males approaching full size)
- Year 6-10: 5-8 inches (females still growing slowly)
Growth basically stops once they hit sexual maturity. Males mature at 2-4 years, females at 6-10 years.
Northern populations grow slower and take longer to mature. A female in Canada might take 12-15 years to reach breeding size.
What Affects Final Painted Turtle Size?
Several factors determine how big your painted turtle will actually get.
- Diet quality has a massive impact. Turtles fed varied, nutritious diets grow larger than those eating junk food.
- Water temperature matters more than you’d think. Painted turtles in warmer waters tend to grow faster and larger.
- Habitat size plays a role too. Turtles in bigger enclosures or ponds generally grow larger than cramped ones.
- Genetics set the upper limit. A Southern painted turtle will never grow as big as a Western, no matter what.
- Health issues can stunt growth permanently. Shell infections, vitamin deficiencies, and parasites all limit size.
Population location affects size significantly. Turtles in northern climates often grow larger than southern populations of the same subspecies.
Painted Turtle Size Chart By Age
This chart shows approximate sizes for a healthy female Western painted turtle (the largest subspecies):
| Age | Shell Length | Notes |
|---|---|---|
| Hatchling | 1 inch | Size of a quarter |
| 6 months | 1.5-2 inches | Fast growth phase |
| 1 year | 2-3 inches | Still growing quickly |
| 2 years | 3-4 inches | Growth slowing |
| 3 years | 4-5 inches | Approaching maturity |
| 5 years | 6-7 inches | Males fully grown |
| 7 years | 7-8 inches | Females still growing |
| 10+ years | 8-10 inches | Maximum size reached |
Males reach their full size 2-5 years faster than females.
How to Measure Your Painted Turtle
Measuring your turtle correctly is pretty straightforward.
You want to measure the carapace length – that’s the top shell from front to back. Don’t measure the curve, measure straight across.
Place your turtle on a flat surface. Use a ruler or measuring tape.
Put one end at the front edge of the shell. Read the measurement at the back edge.
Don’t measure the plastron (bottom shell) unless you’re specifically checking plastron length. Most size references use carapace length.
Never force your turtle to stretch out. Just measure the shell as it naturally sits.
Common Painted Turtle Size Mistakes
People screw up size estimates all the time. Here’s what NOT to do.
Don’t judge age by size alone. A poorly fed 5-year-old might be the same size as a well-fed 2-year-old.
Don’t expect tank size to limit growth. This is a myth – turtles don’t “grow to fit their tank” like goldfish supposedly do (which is also false, by the way).
Don’t assume all painted turtles are the same size. Subspecies matter hugely.
Don’t confuse shell length with total length. When people say “10 inches,” they mean the shell, not including head and tail.
Don’t panic if growth seems slow. Painted turtles grow in spurts, not steadily.
Tank Size Requirements By Turtle Size
Your turtle’s size determines minimum tank requirements.
- Hatchling to 2 inches: 10-20 gallon tank
- 2-4 inches (juvenile): 40-55 gallon tank
- 4-6 inches (sub-adult): 75-90 gallon tank
- 6+ inches (adult): 100+ gallon tank or outdoor pond
These are minimums. Bigger is always better for these active swimmers.
A 10-inch female Western painted turtle really needs 100+ gallons to thrive. Cramming her in a 40-gallon tank is cruel.
Calculate roughly 10 gallons of water per inch of shell. Multiple turtles need way more space.
Do Painted Turtles Grow Throughout Their Life?
Painted turtles don’t grow forever, but they do grow longer than you might expect.
Most growth happens in the first 5-10 years. After sexual maturity, growth slows to a crawl.
Males basically stop growing after maturity (4-5 years). Females keep growing slowly until about age 10.
Some very old turtles show tiny amounts of growth even in their 20s. But it’s minimal – maybe 1-2mm per year.
Wild painted turtles over 30 years old are typically at their absolute maximum size. They won’t get any bigger.
Maximum Painted Turtle Size Records
The absolute largest painted turtles on record are impressive.
The biggest Western painted turtle ever measured was 9.8 inches. That’s nearly 10 inches of colorful turtle.
For Eastern painted turtles, the record is around 7 inches. Southern painted turtles max out at about 6.1 inches.
Midland painted turtles have reached 7 inches in the wild. But averages are more like 5-6 inches.
These record sizes are outliers. Most turtles never reach these maximums.
A 10-inch painted turtle is like a 7-foot-tall human – rare but possible.
Size Comparison: Painted Turtles vs Other Species
Painted turtles are small to medium-sized compared to other common pet turtles.
Red-eared sliders grow 8-12 inches, making them bigger than most painted turtles. Map turtles are similar in size to painted turtles at 4-10 inches.
Box turtles range 4-8 inches, comparable to painted turtles. Snapping turtles absolutely dwarf them at 8-18 inches or more.
Among painted turtle subspecies, size differences are huge. A 10-inch Western painted turtle is twice the size of a 5-inch Southern painted turtle.
How to Tell If Your Painted Turtle Is Full Grown
Figuring out if your turtle is done growing takes some detective work.
Age is the best indicator. If your female is 10+ years old, she’s probably maxed out. Males are done by age 5.
Growth rate slows dramatically at maturity. If your turtle hasn’t grown in 2 years, growth has likely stopped.
Sexual characteristics appear at maturity. Males develop long claws, longer tails, and slightly concave plastrons.
Size comparison to subspecies averages helps. A 7-inch Western painted turtle might still have room to grow.
If you’ve kept records, compare annual growth. Once it drops below 1-2mm per year, they’re basically done.
Why Painted Turtle Size Matters
Knowing your turtle’s adult size is crucial for proper care.
Tank planning depends entirely on final size. That cute 2-inch baby becomes a 10-inch swimming machine.
Filter capacity needs to match adult turtle waste production. Small filters can’t handle large turtles.
Feeding amounts scale with size. A 10-inch turtle eats way more than a 5-inch turtle.
Lifespan expectations matter too. These turtles live 25-40 years, so that baby is a decades-long commitment.
Handling safety changes with size. A 10-inch turtle with a strong bite is harder to manage than a 4-inch one.
What If My Painted Turtle Isn’t Growing?
Stunted growth is a red flag that something’s wrong.
Poor diet is the number one cause. Turtles need varied protein, vegetables, and proper supplements.
Inadequate UVB lighting prevents shell growth and causes metabolic bone disease. They need UVB for calcium absorption.
Water temperature too cold slows metabolism and growth. Painted turtles need 75-80°F water.
Parasites steal nutrients and stunt growth. A vet can test for internal parasites.
Shell disease diverts energy from growth to fighting infection. Treat any shell problems immediately.
If your 3-year-old turtle is still 2 inches long, something’s seriously wrong. Get a vet checkup ASAP.
Painted Turtle Size FAQs
How big is a 1-year-old painted turtle?
A healthy 1-year-old painted turtle should be 2-3 inches in shell length. They grow rapidly during their first year, often doubling their hatchling size. Growth rates vary based on diet, temperature, and subspecies.
What’s the smallest painted turtle subspecies?
The Southern painted turtle is the smallest, typically reaching only 4-6 inches as adults. They rarely exceed 6.1 inches even under ideal conditions. This compact size likely evolved due to competition with other turtle species in their habitat.
Do painted turtles grow to fit their tank?
No, this is a harmful myth. Painted turtles grow according to genetics, diet, and health – not tank size. Keeping them in small tanks doesn’t limit growth, it causes stress, deformities, and health problems. Always provide appropriate space for their adult size.
How fast do painted turtles grow in captivity?
Captive painted turtles with proper care grow slightly faster than wild turtles. They typically reach 2-3 inches by year one, 3-4 inches by year two, and continue growing until maturity at 4-10 years depending on sex. Wild turtles grow slower due to limited food and colder temperatures.
At what age are painted turtles fully grown?
Males reach full size around 4-5 years old. Females take longer, typically reaching maximum size by 10 years old. Northern populations mature later than southern ones, with females sometimes taking 12-15 years to reach full size.
Final Thoughts
Painted turtles come in a range of sizes depending on their subspecies and sex. Western painted turtles are the largest at up to 10 inches, while Southern painted turtles stay compact at 4-6 inches.
Females always outgrow males by 1-2 inches regardless of subspecies. Plan your turtle’s housing based on their expected adult size, not their current baby size.
Remember that these turtles live 25-40 years – that tiny hatchling will be a full-sized adult sharing your home for decades.
About Author
Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.
